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Created: 2025-10-11
Bradley, S. and Watson, J. (2025). Testing and cancer diagnosis in general practice. BMJ Quality & Safety, [online] 34(6), pp.351–354. doi:https://doi.org/10.1136/bmjqs-2024-017921.
This editorial by Stephen Bradley and Jessica Watson discusses a study by Akter and colleagues that examined the use of primary care investigations prior to cancer diagnosis in England. The authors explore the complexities and potential drawbacks of increasing diagnostic testing in general practice to improve cancer outcomes.
Background: The UK's historically poor cancer outcomes have been partly attributed to the gatekeeper role of General Practitioners (GPs) and a lower tendency to use diagnostic tests compared to other high-income nations.
Variation in Testing: The study by Akter et al. found significant variation in the use of diagnostic tests (blood tests, imaging, and endoscopy) among 1,868 general practices before a cancer diagnosis. Practice characteristics accounted for only a small amount of this variation.
Prevalence of Blood Tests: Blood tests were the most common investigation, with 44% of the 53,252 patients studied receiving one before their cancer diagnosis. While abnormalities in a full blood count (FBC) can be a criterion for investigating certain cancers, non-specific blood tests are not otherwise prominent in NICE guidance. However, they can help GPs make decisions when faced with non-specific symptoms.
Uncertain Benefits of Increased Testing: Despite a substantial increase in blood and imaging tests in recent decades, it is uncertain whether the costs and harms are justified by improved patient outcomes. Some observational studies have linked increased use of specific tests, like chest X-rays, to better outcomes for certain cancers , but there is little evidence that more testing overall has improved patient experience. A UK study found no documented evidence of results being communicated to patients in 47% of cases.
Diagnostic Pitfalls: The editorial highlights several challenges in the diagnostic process:
Choosing the right test: A clinician must select the appropriate test for the suspected cancer.
False reassurance: A negative result for one type of cancer may provide misplaced reassurance if the patient's symptoms are caused by a different cancer. For instance, a negative faecal immunochemical test (FIT) for bowel cancer will not diagnose lung cancer.
False negatives: Even with the correct test, a false negative result can occur, requiring a GP's intuition to retest or refer the patient despite the negative result.
The Diagnostic 'Snakes and Ladders': The authors use this analogy to illustrate how testing can either expedite diagnosis (ladders) or prolong it (snakes). An incorrect test or a false negative result can act as a 'snake', delaying the final diagnosis.
Recommendations: The authors argue that simply increasing the volume of all testing is unlikely to be beneficial and could strain healthcare resources. Instead, they advocate for a more focused approach:
Developing interventions that increase the use of specific tests for appropriate patient groups.
Enabling better access to de-identified data on testing volumes to allow general practices to reflect on and understand their usage patterns.
1. Basic Science
The most important insight from basic sciences that a clinician must understand is the heterogeneity of cancer pathophysiology and its often insidious onset. Cancers arise from a multitude of genetic and epigenetic alterations, leading to uncontrolled cell growth and invasion. This process does not always produce specific, localised symptoms in its early stages. For instance, a tumour may be anatomically small but secrete systemic factors that cause vague constitutional symptoms like fatigue, weight loss, or non-specific pain. Furthermore, some cancers, like those of the pancreas or ovary, are located deep within the body and may not cause noticeable symptoms until they are advanced.
This knowledge directly informs diagnostic strategies. Because early symptoms are often non-specific, a clinician cannot rely on a single presenting complaint to pinpoint a diagnosis. This is why, as the article notes, GPs often turn to non-specific blood tests like a full blood count (FBC) or inflammatory markers. An abnormality in these tests, while not diagnostic of a specific cancer, can raise the index of suspicion and justify further, more targeted investigations. Understanding the pathophysiology of different cancers also helps in selecting the right test. For example, knowing that colorectal cancer often bleeds leads to the use of the faecal immunochemical test (FIT) to detect occult blood in the stool.
2. Epidemiology
The most critical epidemiological finding highlighted by the article is the UK's historically poor cancer outcomes compared to other high-income countries. This underscores the urgency of improving early diagnosis. While the article does not delve into specific risk factors, it is crucial for clinicians to be aware of them. Key modifiable risk factors include smoking (linked to lung, bladder, and other cancers), alcohol consumption, obesity, and lack of physical activity. Non-modifiable risk factors include age (the incidence of most cancers increases with age) and family history.
These epidemiological findings should directly inform public health and preventative strategies. Public health campaigns can target modifiable risk factors. For clinicians in primary care, this knowledge is essential for risk stratification. A patient with multiple risk factors (e.g., an older smoker with a family history of lung cancer) presenting with a new cough warrants a lower threshold for investigation than a young, non-smoking patient with no family history. Identifying and managing high-risk populations is a cornerstone of effective cancer prevention and early detection.
Based on the article, a few critical, evidence-based insights deliver a disproportionately high positive impact on cancer diagnosis:
Targeted Testing is More Effective than Volume: The article strongly suggests that simply increasing the volume of all diagnostic tests is unlikely to improve cancer outcomes and may even cause harm by overburdening the healthcare system. The most impactful approach is to focus on increasing the use of specific, appropriate tests for the right patient groups. For example, evidence supports the use of chest X-rays for patients with suspected lung cancer and FIT for those with suspected colorectal cancer. The key is precision, not proliferation.
A Negative Test is Not a Benign Event: A negative test result can provide false reassurance and delay diagnosis. The article highlights two key scenarios:
The Wrong Test: A negative result for a test that does not investigate the actual underlying cancer (e.g., a negative FIT in a patient with lung cancer) can mislead both the clinician and the patient.
A False Negative: Even the correct test can produce a false negative result. Clinicians must maintain a high index of suspicion if symptoms persist or worsen, regardless of a previous negative test.
The Importance of Communicating Results: The finding that results are not communicated to patients in a significant proportion of cases is a critical issue. Effective communication is essential not only for patient safety and experience but also for ensuring appropriate follow-up and further investigation when necessary.
Beyond the highest-impact items, other significant evidence-based practices are essential for providing comprehensive care:
Thorough Clinical Assessment: A detailed history and physical examination remain the cornerstone of diagnosis. These guide the choice of appropriate investigations and help to interpret their results in context.
Adherence to National Guidelines: Following evidence-based guidelines, such as those from the National Institute for Health and Care Excellence (NICE) in the UK, helps to standardise care and ensure that patients receive appropriate and timely investigations.
Safety Netting: This is the practice of explicitly telling a patient when and how to seek further medical advice if their symptoms do not improve, change, or if new symptoms develop. It is a crucial risk management strategy, especially after a negative test result.
Continuity of Care: A long-term relationship between a patient and a GP can be beneficial, as the GP may be more attuned to subtle changes in the patient's health over time.
Use of Risk Assessment Tools: Various tools and algorithms can help GPs to quantify the risk of cancer in patients with specific symptoms, aiding in the decision to refer or investigate.
Appropriate Referral: Knowing when to refer a patient to a specialist is a key skill. Urgent referral pathways for suspected cancer are in place to expedite diagnosis and treatment.
1. Clinical Pearls
"Listen to the patient; they are telling you the diagnosis." A patient's intuition that something is seriously wrong should be taken seriously, even in the face of normal test results.
A new symptom in an older person is cancer until proven otherwise.
Review previous records. A pattern of recurring, seemingly minor complaints may indicate an underlying serious diagnosis.
"If in doubt, discuss." Peer discussion or seeking advice from a specialist can be invaluable in complex cases.
2. Common Pitfalls
Confirmation Bias: Seeking out or interpreting information in a way that confirms one's initial diagnostic impression, and ignoring evidence that contradicts it.
Premature Closure: Accepting a diagnosis before it has been fully verified. For example, attributing a patient's weight loss to stress without ruling out cancer.
Ignoring 'Red Flags': Failing to act on clinical signs or symptoms that are known to be associated with a high risk of cancer.
Over-reassurance: Being overly reassured by a negative test result, leading to a failure to safety net or follow up the patient.
3. Guiding Principles
Shared Decision-Making: Involve the patient in decisions about testing. Discuss the potential benefits, risks, and limitations of each test. Explain what the results might mean and what the next steps will be.
Manage Uncertainty: Be open and honest with patients about diagnostic uncertainty. It is acceptable to say, "I am not sure what is causing your symptoms, but I am concerned, and this is what we will do to find out."
Clear Communication of Results: Ensure that all test results are communicated to the patient in a timely and understandable manner. Explain the significance of the result and the plan for follow-up.
Empathy and Support: A suspected cancer diagnosis is a stressful and frightening experience for patients. Provide emotional support and clear information throughout the diagnostic process.